Tinning of sheet metal



Patented Oct. 10, 1922.

NITED STATES PATENT OFFICE.

OTTO GLASSER, OF LUBECK, GERMANY, ASSIGNOR, BY MESNE ASSIGNMENTS, TO THE CHEMICAL FOUNDATION, INC., A

CORPORATION OF DELAWARE.

TINNIN G OF SHEET METAL.

No Drawing. Application filed July 10,

To all whom it may concem:

Be it known that I, OT'roGLKssER, merchant, a subject of the German Emperor, and resident of No. 50-51 F ackenburgerallee, Lubeck, Germany, have invented certain new and useful Improvements in or Relating to the Tinning of Sheet Metal, of which the following is a specification.

This invention relates to a mode of partially tinning sheets of all kinds and it has for lts object in order to economize in tin, to provide those parts of the sheets which in their ultimate use do not call for atin coating, with a coating adapted to reject the tin during the tinning operation.

According to this invention, therefore, one side of the sheet is covered with a coating of earthy colours which are finely ground in varnish, lac or the like. In the place of earthy colours use may be made of clay or claj earth, and the compounds thereof, such as kaolin, as well as earth of all kinds or relative substances, mineral colours, carbon colours and carbons, for instance graphite,

peat, charcoal, animal coal and stone coal. The tin rejecting coating is applied to one side of the sheet and is then burned in. The sheet thus prepared is then tinned in known manner, either electrochemically, or by means of heat, with. the result that only one side of the sheet becomes coated with tin, while the other tin rejecting side remains uncoated and by its tin rejecting coating is protected against rust.

From those partly tinned sheets box bodies may be made for preserved tins, having folded longitudinal seams. Such longi' tudinal seams could, however, not-be soldered owing to the tin rejecting coating 40 thereof refusing to take the solder. In order to attain this, the edges on opposite sides 1918. Serial No. 244,201.

of the sheets must both be tinned. To this end the tin rejecting coating is provided with omissionsat the places subsequently to be soldered. Sheets thus prepared are then dipped in the tin bath with the result that one side will become wholly tin, while the other side receives a tin coating only at the parts to be subsequently soldered.

similar procedure may be adopted where the sheets are to receive on one or both sides tinned inscriptions, or figural representations, or the like. It is thus possible to effect any desired portional tinning on either or both sides of the sheets. In the latter case the requisite omissions in the tin rejecting coating are provided on both sides, and the sheets arethen dipped in the bath.

What I clai is:

1. A method? of partially tinning sheets which comprises applying to portions thereof a rejecting coat comprising a mineral color finely ground in varnish, then fixing the coating by means of heat, and subsequently tinning the treated sheet, the coated portions remaining unaffected and being substantially permanent.

2. In a method of partially tinning sheets, the steps which consist in applying to portions thereof a rejecting coat comprising a mineral color finely'ground in varnish, and plhen fixing said rejecting coat by means of eat.

3. In a method of partially tinning sheets the steps which consist in applying to the sheet to be tinned a rejecting coat comprising a mineral substance finely ground in varnish, and then fixing said rejecting coat by means of heat.

Signed by me at Lubeck, Germany, this 22nd day of April, 1918.

OTTO GLASSER. 

